I'm looking for something cozy for sitting and reading in my room, but my doorway is 29 inches wide at most and then the stairs going up as seen in the picture are only 30 inches wide, 33 if I take the banister off. I'm not sure where I can get a cozy sofa chair that would fit. I'm considering even like a foam/bean bag chair if I can find a cover that looks chic and not childish. If anyone can think of something or some solution to this that would be helpful.

Other info that might help but is not as important:
I am small, 5'1'' 100 lb so small seating will probably work for me
I'd prefer eco friendly furniture if possible
I like bright colors, especially greens and blues, but dark velvety fabrics are nice too